HP-65 - 1604S01786 - Display faulty or Drivers faulty ?

[albertofenini]

Sorry for that Tony,

we replaced the first block because it was almos clear that the original was a defective block and
the spares used until now were possibly old and damaged themselves.

So it was and when this worked out we
decided to give a try with the second block and to our surprise it worked out.

We can always measure the value now, but to what and where should we measure ?

At the cathode driver ? That was probably digit number 9, counting digit 15 the far most left
which means we should put the probe at pin 1 of the cathode driver, is this correct ?

Let us know, and we will do it
take care !!

[EDIT] sorry, I meant digit number 8, since the number 15 is the first - sign